Temperature control device



April 6, 1937. F. M. KERN TEMPERATURE CONTROL DEVICE 3 Sheets-Sheet 1 Filed March 20, 1935 w M J MMW v v mm r u s m m R w w a N M m w x N HMW W M A H m MM m d M m W F m April 6, 1937. F. M. KERN 2,076,406

TEMPERATURE CONTROL DEVI CE Filed March 20, 1935 3 Sheets-Sheet 2 v INVENTOR E .2. 722d M. my.

4 BY W49 'TORNEY5.

April 6, 1937. M, KERN 2,076,406

- TEMPERATURE CONTROL DEVICE Filed March 20, 1935 3 Sheets-Sheet 3 INVENTOR. 776d M Ker z A TTORNEYS Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE.

10 Claims.

My invention relates to a furnace and particularly to a heat responsive unit which automatically regulates the draft through the furnace to maintain the heated medium passing from the furnace within predetermined temperature limits.

Regulators have been employed heretofore for controlling the movement of the draft doors of the furnace, one in the flue and one in the ash pit, to regulate in some manner the draft through the fire box to thereby control the burning of the fuel and the temperature of the medium heated therey.

My present invention is a material improvement over any device heretofore employed, being sensitive, fool-proof and adjustable. A fluid is employed which expands when heated to actuate the device to cause the door in the ash pit to be closed and the flue door to be opened. This interrupts the passage of air through the fire box and dampens the burning of the fuel. The furnace will continue to heat the medium passing therethrough until it has cooled off a predetermined amount. This cooling will cause the contraction of the fluid and the operation of the device to open the ash pit door and to close the door in the flue to again cause air to pass through the fire box and effect the increased burning of the fuel.

The fluid is encased in a tube which is provided with fins to more readily effect an interchange of heat so that the fluid will immediately respond to changes in temperature of the furnace. This tube is connected to a standpipe wherein a heavier fluid is disposed which does not mix with the expansible fluid and which operates as a flexible piston for operating a metal piston relative to a cylinder to actuate an arm which controls the closing and opening of the doors.

The doors may be so connected to the arm as to operate together, that is to say, one may be closing while the other is opening and means may be so connected as to open or close both doors at the same time when desirable as will be explained hereinafter.

The tube, having the expansible fluid therein,

is preferably disposed in the air passage of a hot 01 mean in the roomto control the temperature all instances the apparatus functions in the same manner to regulate the draft through the fire box to control the burning of the fuel and the heating medium within the'furnace.

Accordingly, the main objects of my invention are to provide a regulating system for a furnace which automatically retains the temperature of a heating medium between predetermined limits; to provide a control device which embodies a pivot and a tube containing an expansible fluid which operates the doors of the furnace to control the draft through the fire box thereof; to provide a piston and a fluid system to which an expansible fluid in a tube is directly connected to operate the piston through the fluid system and control the movement of the furnace door and the flow of air through the fire box; to provide a tube with fins to rapidly effect a change in temperature of the expansible fluid therewithin to be sensitive to small temperature changes when controlling the regulation of the furnace; and, in general, to provide a regulating system for a furnace which is positive in operation, simple in construction and economical of manufacture.

Other objects and features of novelty of my invention will be either specifically pointedout or will become apparent when referring, for a better understanding of my invention, to the following description taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a view in elevation of a furnace having mounted thereon a regulating mechanism embodying features of my invention,

Fig. 2 is an enlarged broken view of the regulating mechanism illustrated in Fig. 1,

Fig. 3 is a sectional view of the structure. illustrated in Fig. 2, taken on the line 33 thereof,

Fig. 4 is an enlarged View, partly in section and partly in elevation, of a portion of the device illust'rated in Fig. 2,

Fig. 5 is an enlarged sectional view of the structure illustrated in Fig. 2, taken on the line 5-5 thereof,

Fig. 6 is an enlarged sectional view of the structure illustrated in Fig. 2, taken on the line 6-6 thereof,

Fig. '7 is a View of a furnace, of the steam or hot water type, having a regulator embodying my invention mounted thereon.

Fig. 81s a sectional view of structure similar to that illustrated in Fig. 3, showing a modified form thereof,

Fig. 9 is a broken View of a further form which my invention may assume, and

Fig. is a sectional view of structure, similar to that illustrated in Fig. 4, showing a modified form thereof.

A furnace ll of the hot air type is illustrated in Fig. 1, as having an outer casing l2 and an 10 inner casing (-notshown), forming the fire box of the furnace from which a flue I3 is connected to a chimney. A door I4 is provided on the furnace through which fuel is introduced into the fire box and an ash door I5 is provided on the front of the ash pit on the bottom of the furnace, having a draft door l6 hinged thereon. The flue l3 has a draft door ll pivoted thereto which operates in conjunction with thedoor Hi to regulate the flow of air through the fire box. When the door I! is closed and the door I6 is open a maximum amount of air will pass through the fire box. If both doors are open only a minimum amount of air will pass through the fire box While when, the door I1. is open and door l6 closed, no air will pass through the fire box. It can readily be seen that through the adjustment of the position of the doors i6 and I! the burning of the fuel can be controlled.

The regulating device 20, which embodies my invention, is supported by a bracket 2| to the top casing 22 of the furnace and comprises a tube 23 projecting inwardly of the casing 22 in the path of air flow between the casing 22 and the inner casing (not shown). The tube 23 is connected to a casting 24 having an extending arm 25 which supports a shaft 26. The shaft 26 is pivoted to a pulley 21 which operates a chain 28 secured to the pulley by a bolt 29. An arm 3| is also pivoted on the shaft 26 and carrying pulleys 32 and 33 on its outer end over which the chain 28 extends. The portion 34 of the chain 28, which, passing over the pulley 32, is connected to the draft door IT of the flue l3. The other branch 35 of the chain 28 extends over the pulley 33 and is connected to the draft door l6.

The angular movement of the arm 3| about the shaft 26 or the manual turning of the shaft causes the chain 28 to be wound and unwound about the pulley 21 to lengthen or shorten the branches 34 and 35 of the chain 28 to cause one door to move toward open position and the other door to move toward closed position or vice versa, as the case may be, depending upon the direction of movement of the arm 3| or the direction of rotation of the shaft 26.

For actuating the arm 3|, I have provided a vertically movable cylinder 36 having a projecting pin 31 near the lower end engaging a slot 38 in the arm 3|. The upward and downward movement of the cylinder 36 causes the arm 3| to tilt about the shaft 26 to operate the draft doors of the furnace as pointed out above. The tube 23, connected to the casting 24, communicates through a boss 39 and a pipe 4| with the upper end of a standpipe 42. The standpipe 42, which is of larger diameter than the pipe 4|, functions as a hydraulic ram for causing the fluid 40, flowing from the pipe 4| onto the fluid 43 in the standpipe 42, to be forced into cylinder 45 to move a piston 44 upwardly to move the cylinder 36. The cylinder 45 is provided with suitable packing head 46 to seal the piston 44 therewithin, while suitable spaced projections 41 and 48 engage sides of the cylinder 36 to position the 'pointer 55 is secured to the shaft 26.

cylinder and prevent any friction with the cylinder 45.

The cylinder 36 is provided with a cap 49 which may be removed to permit the piston 44 to extend therethrough during the installation of the mechanism. The cap 49, when secured to the cylinder 36, is engaged by the end 5| of the piston 44 to thereby effect the raising and lowering of the cylinder 36. A plug 52 is provided in the end of the casting 24 for providing a predetermined pressure on the fluid 43 to force the piston 44 and therefore the cylinder 36 in a desired position.

The fluids 40 and 43 are preferably different. The fluid 46 within the tube 23 is preferably a light lubricating oil such as a Pennsylvania oil known in the trade as Iso-Vis embodying a s0- dium-oleate composition which flashes about 375 degrees and which has a high boiling point. The fluid 43 in the standpipe 42 and cylinder 45 is preferably heavier than the fluid 46 and may comprise 10 parts of glycerine, 1 part of starch and 1 parts of glucose. This substance has a high surface tension and specific gravity and will not mix or emulsify with the light oil in the tube 23. To make such a fluid 43, the starch is mixed with enough water to make it a gelatinous mass to which glycerine is added and heated to a temperature of substantially 284 degrees F., at which temperature the mixture is stirred vigorously. As the mixture cools glycerine is added preferably between the temperature of 200 and 250 degrees which facilitates mixing. This heavy mixture in the standpipe and cylinder functions as a flexible piston which is actuated by the oil in the tube 23. The small tube 4|, connecting the tube 23 to the standpipe 42, prevents a recirculation of the oil 46 when cooled in the tube 23 and there is no possibility of this oil mixing with the heavy fluid 43 in the standpipe 42. The heavy fluid 43 has low adhesion properties which permits it to move readily within the standpipe 42 and the cylinder 45 and has high cohesion properties to prevent the oil mixing therewith. Such fluid has no creeping or drying action and will therefore last for an indefinite time.

The tube 23 is provided with a plurality of fins 53 which causes the tube and the liquid therein to more readily change in temperature following the change of temperature of the air or other fluid surrounding the tube. While the tube 23 may change somewhat in dimensions due to the change in temperature, such change is small relative to the change in volume of the oil46 for a like change in temperature. The change in volume of the oil 40 is depended upon to operate the piston 44 through the fluid 43.

A dial 54 is mounted on the arm 25 and a The opposite end of the shaft 26 may have a sprocket wheel 56 secured thereto for a reason pointed out hereinafter. Through the adjustment of the pointer 55 relative to the dial 54, the position of the doors are changed through the change effected to the shaft 26 and pulley 21. In this manner the position of the doors are changed relative to the arm 3| and the cylinder 36 so that the regulation, eifected by the movement of the cylinder, is changed to provide more or less heat, as is desired.

While this change may be effected manually in the basement through the operation of the dial pointer 55, the same adjustment may be made remotely in an upstairs room, or elsewhere, by the operation of a similar pointer 55 mounted remotely from the furnace for' actuating the pointer 55 at the furnace through a chain 51 operating on the sprocket 56.

As the fluid 40 in the tube 23 contracts after the ash pit door I6 has been closed and flue-door 5 H has been opened and the furnace begins to cool, a spring 58, connected between the top end of the cylinder 36 and the casting 24, draws the cylinder 36 downwardly to thereby operate the arm 3| in a counter-clockwise direction to open the door 16 and close the door l1 and to again cause air to pass through the fire box of the furnace. It will be noted that the natural tend- .ency of the device is to positively close the ash -pit door and to open the flue door to shut down the furnace while the opening of the draft through the fire box is effected by spring tension. This is considered a safety feature of the device.

In Fig. 7, I have shown a further form of my 20 invention applied to a steam or hot water furnace with the controls connected in the usual manner to the ash pit door l6 and to the flue door H. In the hot water or steam furnace illustrated, there is no means provided for the insertion of the tube 23 within the fluid compartment. When the furnace is constructed to have such means, the tube 23 of the device 20 may be disposed directly within the fluid compartment, the same as illustrated on the hot air furnace of Fig. 1. The majority of the present day hot water or steam furnaces lack a connection which will permit the insertion of the tube 23 within the fluid compartment and it is necessary to provide means whereby the tube 23 will be subjected to the temperature of the fluid within the furnace, to oper ate in the same manner as above described relative to the furnace illustrated in Fig. 1. I have provided a conventional flow of the heated fluid of the furnace through a pipe 59 connected to the bottom of the furnace and a pipe 6| connected to the top thereof. A flow of steam or hot water will occur in the circuits 59 and 6| about the tube 23 which is disposed therein. The temperature of the water or steam thus circulated will effect the expansion or contraction of the fluid 46 in the tube to control the burning of the fuel in the furnace as above described relative to the furnace illustrated in Fig. 1.

It has been mentioned hereinabove that under certain conditions it might be desirable to close the draft doors l6 and H simultaneously or to close one when the other is open. To effect such an operation, the control may be that illustrated in Fig. 8. The branches 34 and 35 of the chain 28 are disposed on individual pulleys 63 and 64. The pulley 63 is mounted on the shaft 65 within the tubular bushing 66 to which the pulley 64 is permanently secured. The bushing 66 is supported on the arm 25. A dial 61 is permanently secured to the arm 25 in the same manner as to the dial 54, above described. An index pointer 12 is secured to the bushing 66 and is provided with a plurality of notches 68 engageable by a spring pressed finger 69 carried by an arm II secured to the end of the shaft 65. The two pulleys 63 and 64 are secured in fixed relation relative to each other by the engagement of the finger 69 in a notch 68 and will function as a single pulley, the same as that shown in the system of Fig. 3. Relative adjustment of the doors l6 and H is effected through the positioning of the finger 69 in any one of the notches 68 and after such adjustment is made, the arm II and index finger 12 will operate in unison to effect a 75 change in the position of the doors to control the heat produced by the furnace. When it is desirable to close both of the draft doors l6 and H,

the out-door temperature drops, the fluid 40 in the out-door tube 23 contracts to relieve the pressure of the fluid 46 in the tube 23 in the furnace, to permit the spring 58 to open the door 5 a greater amount and close the door l1. When the out-door temperature rises the pressure of the fluid 40 of the system is increased to effect the reverse operation of the doors.

The tube 23 could also be placed in a room to be heated instead of in the furnace to operate with the fluid 40 in the tube. However, a more critical operation could be effected by employing a gasifying liquid, many of which are well known in the art, which would become a gas under pressure at a critical temperature to function instantly to close and open the doors I! and I6, respectively, to regulate the draft through the fire box. With such an arrangement, regulation occurs relative to the desired temperature of a room rather than between predetermined limits of temperature at the furnace of the fluid which heats the room.

A further form of my invention is illustrated in Fig. 10, wherein the operating piston 44 is eliminated and a rubber sack 14 is employed to receive the heavy liquid 43 disposed in the standpipe 42. The standpipe is connected to a cylinder 1'! having a plug 15 screwed within the head 16 provided on the lower end of the cylinder TI. The plug l5 engages a flange 18 on the bottom of the sack 14 to seal the sack to the cylinder 11. The fluid 43 is introduced into the sack through the standpipe 42 and when pressure is applied to the fluid 43 the sack elongates to move the cylinder 36 upwardly as was effected by the piston 44 in the device illustrated in Fig. 4. A spring 19 is disposed about the sack 14 to prevent the sack from expanding sidewardly and freeze against the inner surface of the cylinder 11. Sideward expansion is reduced by the spring 19 when a pressure is applied to the fluid 43 and the elongation of the sack I4 and the movement of the cylinder 36 readily occurs. The operation of the device and the doors follows that of the device 26 illustrated in Fig. 4 and will not be described further.

It will thus be seen that I have provided a regulator for a furnace which is positive in operation, being so constructed that the shutting down of the furnace is effected positively. The opening of the draft through the furnace is effected by the spring 58 and any failure of the device to function will occur when the furnace is shut down. The device is rugged, simple in construction and provided with a minimum number of moving parts. The device may operate directly from the fluid in the furnace to control the burning of the fuel thereof or may be operated in conjunction with changes in the outdoor temperature to provide a more critical regulation of such burning.

While I have described and illustrated several embodiments of my invention, it will be apparent to those skilled in the art that various changes, omissions, additions and substitutions 5 may be made therein without departing from the spirit and scope of my invention, as set forth in the accompanying claims.

I claim as my invention:

1. A device for regulating the draft doors of a furnace including, in combination, a casting, a rocker arm supported on said casting for actuating the doors, a cylinder secured to said casting, a piston in said cylinder, a movable cylinder extending over said first cylinder and engaging said piston, means interconnecting said arm with said movable cylinder for eifecting its actuation upon movement of the piston, and a heat sensitive device including a tube containing an expansible fluid which operates said piston when the tube is heated.

2. A device for regulating the draft doors of a furnace including, in combination, a casting, a rocker arm supported on said casting for actuating the doors, a cylinder secured to said casting, a piston in said cylinder, a movable cylinder extending over said first cylinder and engaging said piston, means interconnecting said arm with said movable cylinder for effecting'its actuation upon movement of the piston, a heat sensitive device including a tube containing an expansible fluid which operates said piston when the tube is heated, and a spring on said movable cylinder opposing its movement.

3. A device for regulating the draft doors of a furnace including, in combination, a casting, a

rocker arm supported on said casting for actuatirr the doors, a cylinder secured to said casting,

a piston in said cylinder, a movable cylinder extending over said first cylinder and engaging said piston, means interconnecting said arm with said movable cylinder for efiecting its actuation upon movement of the piston, a heavy fiuid for operating said piston, and a heat sensitive device containing an expansible fluid which directly engages and moves said heavy fluid.

4. A device for regulating the draft doors of a furnace including, in combination, a casting, a rocker arm supported on said casting for actuating the doors, a cylinder secured to said casting, a piston in said cylinder, a movable cylinder extending over said first cylinder and engaging said piston, means interconnecting said arm with said movable cylinder for effecting its actuation upon movement of the piston, a heavy fluid for operating said piston, a heat sensitive device containing an expansible luid, and a small tube conducting the fluid of the heat sensitive device to directly contact said heavy fluid to prevent the recirculation and intermixing of the 5. A regulatingdevice for the draft doors of a furnace comprising a pulley, a chain secured to said pulley and connected to said draft doors, an arm pivoted to the shaft of said pulley and having pulleys on the end thereof over which the chain extends to be lengthened or shortened both by the movement of the chain over the pulleys on the end of the arm and the winding and unwinding of the chain over the pulley to which the chain is secured, and heat responsive means for actuating said arm.

6. A regulating device for the draft door of a furnace comprising a pulley, a chain secured to said pulley and connected to said draft doors, an arm pivoted to the shaft of said pulley and having pulleys on the end thereof over which the chain extends to be lengthened or shortened both by the movement of the chain over the pulleys on the end of the arm and the winding and unwinding of the chain over the pulley to which the chain is secured, a piston for actuating said arm, and a fluid expandible when heated to positively operate the arm to regulate the doors to close the draft through the furnace.

'7. A regulating device for a furnace comprising a pulley, a chain secured to said pulley and connected to said draft doors, an arm pivoted to the shaft of said pulley and having pulleys on the end thereof over which the chain extends to be lengthened or shortened both by the movement of the chain over the pulleys on the end of the arm and the winding and unwinding of the chain over the pulley to which the chain is secured, a piston for actuating said arm, a fluid expandible when heated to positively operate the arm to regulate the doors to close the draft through the furnace, and an indicating device for adjusting the position of the doors relative to the pulleys on the end of the arm for changing the regulation of the draft through the furnace relative to the temperature of the fluid heated.

8. In a draft control system for furnaces, a

pair of draft doors, a thermostatic device containing an expansible fluid, a cylinder connected to said thermostatic device, a piston in said cylinder adapted to be actuated by said fluid, a second cylinder telescoping over said first cylinder and connected to said piston, and means connecting said draft doors and said second cylinder to effect thermostatic control thereof.

9. In a draft control system for furnaces, a pair of draft doors, a thermostatic device containing an expansible fluid, a cylinder connected to saidthermostatic device, a piston in said cylinder adapted for actuation by said expansible fluid, a second cylinder telescoping over said first cylinder and connected to said piston, and manually adjustable means interconnecting said second piston and said draft doors to effect a thermostatic control thereof.

10. In a draft control system for furnaces, a pair of draft doors, a thermostatic device for controlling said draft doors, said thermostatic device comprising a base portion having a heat exchange element adapted to extend within said furnace, said base portion having a cylinder formed thereon, a piston in said cylinder, a second cylinder telescoping over said first cylinder, and connected to said piston, a rocker arm serving to control movement of said draft doors pivotally mounted on said base portion and connected to said second cylinder, and an expansible fluid within said thermostatic device for actuating the same.

FRED M. KERN. 

